The St. Louis Chapter was chartered on June 24, 1946. It was the fifteenth chapter to receive its charter. The chapter began with 12 charter members and has expanded to over 900 members representing well over 175 companies and organizations. The chapter's main focus through its 60-plus years of existence has been the interaction and education of its members.

The Chapter sponsors monthly meetings and seminars with presentations by internal audit practitioners and educators, including many presentations by Chapter members. In addition, the sessions feature speakers discussing current integral auditing topics. In order to foster the IIA’s motto of Progress Through Sharing, the Chapter sponsors the Audit Management Roundtable. The roundtables are a discussion forum comprised of the leadership from various St. Louis companies and organizations. The College Relations Committee has sponsored hundreds of students over the years through the Chapter’s “Student Night” Program. The college program enables students to meet practitioners and discuss the internal audit profession.